First I hope none of us will have to deal with hospitals unless you are a doctor,nurse ,cleaner,technician etc
Thanks G-d I know only from visiting patients[rarely] of what is going on with hospital diets and I also have occasionally eaten in a hospital dining room. We should first be thankful that we have plenty to eat, and we should never forget that in our age and culture we are so spoiled.!
If I could give only ONE SINGLE advice: take care that only healthy oils/fats are used and this alone will already have a dramatic effect.
I can say this with more than 40 years of experience with many thousands of patients. I have written enough about these oils and fats and may do again in the future
[basically the best quality olive oil and sesame oil]
Salt restriction is of course important, but this can’t be done axiomatically as there are too many differences between individual needs, but indeed everyone should be able to add what he thinks he needs and salt does not need to be added in the cooking!
Medicines, supplements? Impossible to generalize but no one should go unchecked for B12 deficiency when admitted to a hospital ,for sure to any neurological department!